The answer is not so simple. First of all, the foundry matters. And if your company is an important client or not. And, depending on the tech node, the load in the fabs is of importance. And you can do hot lot or super hot lot or shuttle, … . There are fast and more expensive ways and there are slower, less expensive ways. You can also put more metal layers, they support a range from x to y. More metal layers is easier routing, more metal layers is more expensive. These are just a few factors out of the top of my head. Start thinking at a million for older tech and more for latest tech (a lot are taping out in 16/14nm nowadays). For low volume, small companies, a shuttle is the low cost solution to go for. The big ones, TSMC, UMC, … they know their stuff, expect more issues with smaller foundries.